* Ensure that the `--ref` flag cannot be used in conjunction with a cache ID.
* Update error handling to provide clear feedback when this condition is violated.
* Add tests to cover scenarios involving the `--ref` flag and cache ID.
* Added validation to ensure that the `--ref` flag cannot be used when a cache ID is provided.
* Updated error message to include the reference when a cache is not found with the specified `--ref`.
* Replaced direct conversion of cache ID string to int with a dedicated `parseCacheID` function.
* Improved readability and maintainability of the `deleteCaches` function.
* Changed the error message from "--ref cannot be used without cache key/ID" to "must provide a cache key" for clarity.
* Updated corresponding test case to reflect the new error message.
* Clarified the description of the `--ref` flag to specify its purpose more accurately.
* Ensures users understand that it narrows down deletion by cache key and ref.
- Introduced `--ref` flag to narrow down cache deletion to a specific branch or PR reference.
- Updated command examples to include usage of `--ref`.
- Added validation to ensure `--ref` cannot be used with `--all` and must accompany a cache key/ID.
